Roger Spencer (BSc (Hons), MSc, PhD, Cert, Gard.) is Senior Horticultural Botanist at the Royal Botanic Gardens Victoria in the Plant Identification Service. He has written many popular and scientific articles on horticultural topics and books on Elms, Grey and Silver Foliage Plants, and a recent 5-volume Horticultural Flora of South-eastern Australia. Rob Cross (BSc, BAppSci(Hort)) is passionate about plants, their use and their conservation. He is a horticultural botanist at the Royal Botanic Gardens Victoria where he deals with plant names on a daily basis, ensuring that plants in the Gardens' Living Plant Collection have the current correct name applied to them. Rob has written scientific papers, a booklet on Japanese Flowering Cherries and contributed to other horticultural books.